The image gathering and processing system requested will be used primarily by five neurobiologists in the UCSD Biology Department to study basic properties of nerve cells. Physiological, structural and biochemical properties of these cells will be studied to answer such questions as: How do the particular electrical properties of the nerve cells come into being? How are the various electrical and chemical sensitivities restricted to particular regions of the nerve cell membrane? What forces guide the outgrowing nerve cell processes? How do the processes know when and where to branch? What are the cues that enable an outgrowing process to recognize its appropriate targets? What are the molecular events that go into forming a synapse, the contact between two nerve cells? How does the nerve cell know when to start making its appropriate neurotransmitter, enabling it to communicate with other cells? How does it know how strong the connection should be? How do the nerve cell circuits thus formed lead to useful perceptions of the world and coordinated behavioral acts? In the past decade, very powerful new biotechnical advances have been made that make some of these questions answerable. Of particular importance have been the discovery of specific markers for different cellular components, and the perfection of the techniques for making monoclonal antibodies. We are now making use of these techniques, but we are limited by the sensitivity and resolution of our optical systems. By wedding these new biological techniques with the most advanced video technology, developed both by the commercial television industry and the space program, we will be able to approach the questions enumerated above at a level of precision and directness never before possible.